1. Field of the Invention
The present invention relates to a ski boot with a rigid shell, whose upper, at least partially journalled around a shell base, is constituted on the one hand, of a collar made of at least one pivoting portion on the shell base and, on the other hand, of the rear end of a foot-covering spoiler which closes the front opening of the shell base after insertion of the foot into the boot so as to ensure good retention of the foot and the front portion of the lower part of the leg.
2. Description of Background and Relevant Information
Known ski structures of the aforementioned type must fulfill different obligations. They need especially to use rigid materials for the manufacture of their shell so as to be able to instantly transmit the impulsions of the foot of the skier, thereby allowing precise control of the skis during skiing. To this end, the foot and the heel are generally tightly held in the boot by adjustable portions more or less flexible and/or anatomical, and are protected from all damage at the level of their journals by the rigid parts of the shell, journalled between themselves and relatively spaced from the adjustable portions. Such boots also protect the foot from shocks and external shocks, in particular shocks from running edges of the ski.
European Patent Application No. 0171685 shows a ski boot of this type. In this application, a slot extends longitudinally from the upper front end of the shell base to the front edge of the upper where it ends. A pivoting front cuff on the end of the shell base covers the slot and extends as far as the lower part of the leg where it connects with a rear spoiler to ensure the closing of the upper. As taught by this document, the foot retention is done by means of a central locking comprising a traction and linkage element interacting between the tongue and the shell base, such that they get closer to each other. The same central locking also frees them for a certain amount of displacement, a function of the loosened length of the traction element, so as to facilitate the engaging or the retraction of the foot when the upper of the boot is open. As it appears clearly, this possibility of displacement is, thus, without limit well-defined since it depends on the loosening done by virtue of the central locking. Furthermore, since the retention of the boot is a function of the tension exerted by the traction element on the cuff and the shell base and thus, the coming together of the latter with respect to each other, the front cuff is more or less lowered depending on the size of the foot. According to this concept of foot retention, where the front cuff does not have a free abutment, or even the reference in its lowered position on the sides of the shell base from one end to the other of the longitudinal slot which it covers, the front cuff is capable of lowering itself further, after adjusting the position of the foot during skiing, especially during front supports biasing the upper of the boot in flexion. The result is some loosening of the traction element which is detrimental for foot retention and therefore detrimental for a precise control of the skis.